Cleaning apparatus for cleaning an image carrier, process cartridge having a cleaning apparatus for removing remaining developer on an image carrier, and image forming apparatus having a cleaning member for removing remaining developer on an image carrier

ABSTRACT

A cleaning apparatus for an image carrier includes a cleaning member for removing remaining developer left on the image carrier; and a sealing member disposed on each opposite end of the cleaning means for preventing the developer removed by the cleaning member from leaking out. The sealing member cleans a surface to which a distance-ensuring device for maintaining a prescribed distance between the image carrier and another electrophotographic process means, extends, and contacts with the image carrier.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a process cartridge using anelectrophotographic method or an electrostatic recording method and animage forming apparatus using the process cartridge.

2. Description of Related Art

To form images, image forming apparatuses using an electrophotographicmethod or an electrostatic recording method form, by selective exposure,latent images on an image carrier, uniformly charged, serving as anelectrophotographic photosensitive body by a charging means, visualizethe latent images by a developing means, and transfer the developedimages onto a recording medium. After the developed images aretransferred, remaining developer (hereinafter referred to as “wastetoners”) left on the image carrier is cleaned by a cleaning means andreused for image formation upon being charged uniformly.

A process cartridge has been practically used recently in which processmeans, such as charging means, developing means, cleaning means, acleaning container, and so on, are made in a united structure. A usercan replace the parts, such as the developers, the image carrier, and soon with those by placing the process cartridge in the apparatus body,thereby rendering the maintenance easier.

Since the image carrier generally has extended the life time of thecarrier, recently favored usage, which renders the maintenance easierand corresponds to life times of the essential parts is done bydesigning a developing means, having some limitation for supplyingcapability, into an independent cartridge and by designing the remainingprocess means, such as an image carrier, a charger, a cleaning means,and so on, into a drum cartridge, in a united body.

FIG. 4 shows an example of a conventional process cartridge. The processcartridge 100 shown in FIG. 4 is the above drum cartridge, whichincludes an image carrier 101, a cleaner blade 102 serving as a cleaningmeans, and a cleaning container 104 accumulating the waste toners.

The cleaner blade 102 has an elastic contact portion 102 a supported bya support member 102 b in contact with the image carrier 101 and removesthe waste toner remaining on the surface of the image carrier 101. Asealing member 103 made of a material such as mortoprain, sponge, felt,or the like is provided on the opposite ends of the cleaner blade 102 toprevent the waste toner from leaking out of the cleaning container 104.The cleaning container 104 has a volume capable of adequately containingwaste toner occurring at the cleaner blade 102 within the life time ofthe image carrier 101, and can be removed at the time of replacement ofthe drum cartridge.

Particularly, in a case of a development method using a jumpingdevelopment or magnetic brush development, it is important to position adeveloper carrier (development sleeve) for developing images with highaccuracy at a prescribed distance with respect to the image carrier 101.Therefore, a contacting roller 105 or the like as a distance ensuringmeans manufactured with high accuracy is generally placed on each end ofthe image carrier to ensure the proper distance between the imagecarrier 101 and the development sleeve (not shown).

In such a case, if the contacting surface 101 a of the contacting roller105 on the image carrier 101 becomes dirty with scattered toner, thetoner may adhere to the contacting surface 1O1 a, and the prescribeddistance may not be kept, disadvantageously. Therefore, the placement ofa cleaning member 106, as a part separated from the sealing member 103provided on the opposite ends of the cleaner blade 102, has beenimplemented recently for cleaning the contacting surface 101 a of thecontacting roller 105.

Where the sealing member 103 and the cleaning member 106 are separatedmembers, as shown in the apparatus in FIG. 4, however, developers mayaccumulate on unclean areas particularly in the process cartridge havinga longer life time because the space between those members 103, 106cannot be cleaned, and the accumulated developers may drop into theapparatus body to disadvantageously make the apparatus inside dirty.

It is therefore an object of the invention to provide a cleaningapparatus, a process cartridge, and an image forming apparatus reducingthe uncleanness inside the apparatus by proposing a cleaning method forthe surface of the image carrier having no unclean area.

SUMMARY OF THE INVENTION

To solve the above problems, a representative structure of the cleaningapparatus, according to the invention, includes a cleaning member forremoving a remaining developer left on the image carrier, and a sealingmember disposed on each opposite end of the cleaning means forpreventing the developer removed by the cleaning means from leaking out,the sealing member cleaning a surface to which a distance-ensuringmeans, for maintaining a prescribed distance between the image carrierand another electrophotographic process means, extends and contactingthe image carrier.

Since the sealing member that is provided on each opposite end of thecleaning means is extended to a surface on the image carrier contactingthe distance-ensuring means for cleaning the surface, the processcartridge can eliminate an area at which scattered toner arrives, sothat the process cartridge can reduce the uncleanness inside theapparatus. Because the members are made in a united body, the number ofparts is reduced, and the manufacturing process and the cost of parts ofthe cleaning apparatus can be reduced, so that the productivity can beimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an entire structural view showing an image forming apparatusaccording to an embodiment of the invention;

FIG. 2 is a front view showing a process cartridge according to anembodiment of the invention;

FIG. 3 is a side view of a sealing member: and

FIG. 4 is a front view showing a conventional process cartridge.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2, a process cartridge and an image formingapparatus of embodiments according to the invention are described.

[Whole Structure]

The image forming apparatus 1 shown in FIG. 1 is a color laser printer.As shown in FIG. 1, the image forming apparatus includes an imagecarrier 15 rotating at a fixed rate, an image forming section made of asecured black developing unit 21K and a rotary developing unit 20 havingthree color developing units, an intermediate transfer body 9 forholding color images developed and overlapped at the image formingsection and transferring the images onto a recording medium S fed from afeeding section. The recording medium S on which color images aretransferred is conveyed to a fixing section 25, and the images are fixedon the medium under the application of heat and pressure. The recordingmedium S is then delivered by a delivery roller to a delivery section 37located at a top surface of the apparatus body. It is to be noted thatthe rotary developing unit 20 and the immobilized black developing unit21K are constituted respectively to be detachably attached to the bodyof the image forming apparatus 1. Each section of the image formingapparatus 1 will be described in detail next.

The drum cartridge 13 is constituted in a united body of the imagecarrier 15, and a cleaning container 14 also serving as a holder for theimage carrier 15. The drum cartridge 13 is supported detachably to theapparatus body and can be replaced as a unit basis easily in accordancewith the life time of the image carrier 15. In this embodiment, theimage carrier 15 is constituted of an aluminum cylinder having adiameter of about 62 mm coated with an organic photo-conductive layerand is rotatively mounted. A cleaner blade 16 serving as a cleaningmember, and a primary charging means 17 are disposed on a periphery ofthe image carrier 15 and are rotatively drive by a drive force from adrive motor, not shown, according to an image formation operation. Thecleaning container 14 is as described below.

The primary charging means 17 uses a contact-charging method, in which aconductive roller is made to be in contact with the image carrier 15.The surface of the image carrier 15 can be charged uniformly by theapplication of a voltage to the conductive roller.

The image carrier 15 is subject to exposure at a scanner section 30.That is, when an image signal is given to a laser diode, the laser dioderadiates image light corresponding to the image signal to a polygonmirror 31. The polygon mirror 31 rotates at a high rate by a scannermotor, not shown, and the image light reflected on the polygon mirror 31selectively expose the surface of the image carrier 15 rotating at afixed rate through image forming lenses 32 and a reflex mirror 33,thereby forming static latent images on the image carrier.

The developing means is constituted of the rotary developing unit 20having the respective color developing units, a yellow developing unit20Y, a magenta developing unit 20M, a cyan developing unit 20C, and asole black developing unit 21K.

The black developing unit 21K is a secured developing unit. A sleeve21KS is disposed with a very small space to the image carrier 15 at aposition corresponding to the image carrier 15 and forms visible imageson the image carrier 15 by black toner. The black developing unit 21Kfeeds toner in the container by a feeding mechanism, coats the toner asa thin layer on an outer periphery of the sleeve 21KS rotating in aclockwise direction in FIG. 1 by a coating blade 21KB, made in pressedcontact with an outer periphery of the sleeve 21KS, and gives electriccharges to the toner. When a development bias is applied to the sleeve21KS, the electrostatic latent image of the image carrier 15 isdeveloped with the toner.

The rotary developing unit 20 is supported detachably to a developmentrotary member 23 rotating around a shaft 22 as a center, and for formingimages, the respective developing units move rotationally around theshaft 22 and stop the rotation at a position such that a predetermineddeveloping unit faces the image carrier 15. After sleeves 2OYS, 2OMS,20CS are positioned to face the image carrier 15 with a very small space(about 300 μm), visible images are formed corresponding to theelectrostatic latent images on the image carrier 15. When a color imageis formed, the developing rotary member 23 rotates as one rotation ofthe intermediate transfer body 9, and a developing process is done bymeans of the yellow developing unit 20Y, the magenta developing unit20M, the cyan developing unit 20C, and the sole black developing unit21K, in this order, so that each color is transferred to theintermediate transfer body 9 and overlapped at the body 9. After thetoner images are transferred onto the intermediate transfer body 9, thedeveloper remainders, which remain on the image carrier 15, or namelythe waste toner, are removed by the cleaning means as described below.

FIG. 1 shows a state that the yellow developing unit 20Y is placed andmade still at a position that the unit faces to the image carrier unit.The yellow developing unit 20Y feeds the toner in the container to acoating roller 20YR by a feeding mechanism, coats the toner as a thinlayer on an outer periphery of the sleeve 20YS rotating in a clockwisedirection in FIG. 1 by means of the coating roller 20YR rotating in aclockwise direction in FIG. 1 and a coating blade 20KY, and giveselectric charges (triboelectric charges) to the toner. By application ofthe development bias to the sleeve 20YS facing the image carrier 15 onwhich latent images are formed, development is made with toner on theimage carrier 15 corresponding to the latent images. Image formation forrespective colors is made in substantially the same way with respect tothe magenta developing unit 20M and the cyan developing unit 20C.

The sleeves 20YS, 2OMS, 20CS of the rotary developing unit are connectedto a drive power and respective high voltage sources for the respectivecolors formed in this printer body when each developing unit movesrotationally to the developing position, and the voltage is selectivelyand sequentially applied for each color developing unit where each unitis driven.

The intermediate transfer body 9 rotates in the clockwise direction inFIG. 1 in synchrony with the outer peripheral speed of the image carrier15, and receives multiple transfers by four transfers (images of fourcolors, CMYK) of visualized toner images on the image carrier 15 by therespective developing units when color images are formed. Theintermediate transfer body 9 that received the multiple transfersfurther transfers the color toner images on the intermediate transferbody 9 at one time onto the recording medium S by conveying therecording medium S through sandwiching the medium S with the transferroller 10 to which the voltage applies.

The intermediate transfer body 9 according to the embodiment has analuminum cylinder 12 having a diameter of 186 mm and an outer peripherycovered with an elastic layer 11 made of materials such as anintermediate resistance sponge and intermediate resistance rubber. Thean intermediate transfer body 9 is rotatively supported and rotates upontransmission of drive force by means of gears, not shown but securedunitedly

The recording medium S is stacked on a cassette 2 provided at a lowerportion of the apparatus body. The recording medium S, after being fedby a pickup roller 3 and separated by a feeding roller 4 and a retardroller 5 sheet by sheet, is conveyed by guided by a feeding guide 6 andsent to the register roller 8. The register roller 8 does a non-rotationoperation that renders the recording medium S in a stop and wait stateand a rotation operation that renders the recording medium S conveyedtoward the intermediate transfer body 9 according to a prescribedsequence, thereby correcting oblique feeding of the recording medium Sand conveying the recording medium S in synchrony with the intermediatetransfer body 9.

The transfer roller 10 winding an intermediate resistance foamed elasticbody over a metal shaft is provided to be capable of contacting with andseparating from the intermediate transfer body 9. While the four colortoner images are formed on the intermediate transfer body 9, or whilethe intermediate transfer body 9 turns multiple times, the transferroller 10 is located at a position spaced from the intermediate transferbody 9 as shown by a solid line in FIG. 1 so as to keep the images inorder. When the recording medium S is conveyed after the color tonerimages are formed on the intermediate transfer body 9, the transferroller 10 is urged with a prescribed pressure to the intermediatetransfer body 9 through a recording medium S as shown by a broken lineby means of a cam not shown.

A bias is also given to the transfer roller 10 at that time, therebytransferring the toner images on the intermediate transfer body 9 to therecording medium S. The intermediate transfer body 9 and the transferroller 10 are driven respectively, so that the recording medium S is ina state that sandwiched by the intermediate transfer body 9 and thetransfer roller 10, is subject to a transfer process and at the sametime, is conveyed at a prescribed rate toward the fixing section 25 asthe subsequent process.

The fixing section 25 is for fixing the toner images transferred on therecording medium S and includes a fixing roller 26 for applying heat,and a pressure roller 27 for pressing the recording medium S to thefixing roller 26. The respective rollers 26, 27 are hollow rollers andhave respective heaters 28, 29 inside, thereby conveying the recordingmedium S upon being rotatively driven.

That is, the recording medium S holding toner images is conveyed by thefixing roller 26 and the pressure roller 27, and when heat and pressureare applied, the toner images are fixed on the recording medium S. Therecording medium S to which the images are fixed is conveyed by aconveyance roller 34 and a conveyance roller 35 and is delivered to thedelivery section 37 by a delivery roller 36 to be stacked, therebyfinishing the image formation.

[Process Cartridge]

Referring to FIG. 2, the drum cartridge 13 as a process cartridgeaccording to the invention is described next. The drum cartridge 13 asdescribed above is constituted of an image carrier 15, and a cleaningcontainer 14 for accumulating in the cleaning container 14 waste tonersremoved from the image carrier 15.

Cleaning processing is made by the cleaner blade 16 attached to thecleaning container 14 and a cleaning blush not shown. The waste tonerson the image carrier 15 enter in the cleaning container 14 by going by ascooping sheet 18, and are scraped by first the cleaning brush and thenthe cleaner blade 16. The scraped waste toners are scooped up by thescooping sheet 18 and collected in the cleaning container 14. Thecleaning container 14 may not be filled with the waste toner accumulatedin the container 14 earlier than the life time of the image carrier 15,so that the cleaning container 14 can be replaced together at a time ofreplacement of the image carrier 15 when reaching the life time.

In the cleaning container 14, a support member 16 b is so secured at afront surface of the cleaning container 14 by securing members 40 suchas screws or the like that an elastic contacting portion 16 a of a tipof the cleaner blade 16 is in contact with the image carrier 15 with aprescribed entering amount.

A sealing member 41 for preventing the waste toners from leaking out ofthe cleaning container 14 is attached on each opposite side of thecleaner blade 16 on the cleaning container 14 as to contact the imagecarrier 15. As a sealing member 41, it is preferable that the surfacecontacting with the image carrier 15 has sealing property and slidingproperty, and in this embodiment, a fabric member, in which a PTFE fiberis formed in a pile shape, is used as the sealing member. The sealingmember can be any material as long as it has the required sealingproperty and sliding property so that, for example, a fabric member ofan electrostatic transplant, felt, or the like may be used. To preventthe sealing property from being impaired, the sealing member preferablyhas a double-layered structure in which a cushion material, such asfoamed urethane or the like, is provided on the back surface of thesealing member.

A contacting roller 42 serving as a distance-ensuring means,manufactured with high accuracy, is disposed at a position correspondingto each end of the image carrier 15, and is rotatively supported arounda roller shaft 42 a. The contacting roller 42 is in contact with theimage carrier and the sleeves 20YS, 20MS, 20CS, and 21KS and ensures theprescribed distance between the image carrier and the sleeves.

The sealing member 41 is molded as to extend up to the opposite end ofthe image carrier 15, and includes a sealing portion 41 a serving as aseal, and an extended portion 41 b. Therefore, the sealing portion 41 afunctions as to prevent the waste toners from leaking out, and theextended portion 41 b is in contact with the contacting surface 15 a onthe image carrier 15 contacting to the contacting roller 42 and cleansthe contacting surface. Accordingly, even where foreign objects, such asscattered toners, are attached between the contacting roller 42 and thecontacting surface 15 a, the surface can always keep the state by wipingthe surface with the extended portion 41 b, so that the apparatus canmaintain the distance between the image carrier 15 and the sleeve.

Because the extended portion 41 b is in a united body with the sealingportion 41 a, there is no space between the sealing member and thecleaning member, so that the image carrier may not have any space onwhich scattered toners remain. The number of parts to be attached isfurther reduced, so that the process cartridge can reduce themanufacturing process and the costs for parts and can improve theproductivity as well.

With the above embodiments, the fabric member is used as the sealingmember 41, and the form of the fabric member is illustrated in referenceto FIG. 3. FIG. 3 shows a plan view and side view of the fabric member,and the plan view located above shows a part in FIG. 2 in an enlargedview. Numeral 16 b in the plan view is a receiving sheet for toner madeof a thin film sheet, and the sheet is attached and secured below theblade 16 a of the cleaning housing 14. That is, the toner scraped by theblade 16 a are guided and collected by the receiving sheet into thecleaning housing.

Innumerous fabrics 41 c, constituting the fabric member, are inclinedtoward the opening made of the blade 16 a of the housing, the sealingmember 41, and the receiving sheet 16 b, as shown in the side viewlocated below in FIG. 3. A permissive range of the inclined state maybe, as shown in this plan view, as far as within 90° with respect to theopening side, and preferably, within 45° to 60°, which would be noproblem.

The effects for preventing the toner from scattering and for cleaningportions corresponding to the roller of the developing roller can beadequately accomplished where the fabric member 41 is inclined towardthe opening and where the inclined direction is within the above rangeeven if shifted.

Particularly, where the fabric member is inclined, the toners about toscatter from the opening side can be captured, and at the same time, theinclined fabrics can improve the above cleaning effect.

It is to be noted that as another example equivalent to the above roller42, the roller shaft 42 a in FIG. 2 and as a developing roller, a spacerformed on each opposite end of the roller 42 may be used. In addition, aspacer member or members provided to a charger, a transfer unit, or anintermediate transfer unit around the vicinity of the image carrier whennecessary are very useful.

The sealing member disposed on each opposite end of the cleaning meansis structured to extend to a surface to which a distance-ensuring meansdisposed on the image carrier contacts, to clean it, and therefore, incomparison with a structure that a cleaning member, for cleaning thecontact surface of the distance ensuring means, is newly added, noslight gap (uncleaned area) may be otherwise provided between thesealing member and this cleaning means, so that the scattered tonerclinging to that portion could further completely eliminate a worrisomemess on the transfer roller, serving as the transfer means, and ends ofthe transfer materials.

Since the sealing member (cleaning member) covers entirely an intervalbetween the cleaning means and the distance-ensuring means, the cleaningdistance to the distance-ensuring means can be used most effectively,and the cleaning means can be utilized as a cleaning means having alonger life time.

The above structure has separated functions for substantially preventingleaks and for cleaning, so that a longer life time can be provided.

Since the sealing member and the cleaning member are made in a unitedbody, assembling of the members can be made simpler, and this can reducethe costs for assembling and mistakes such as the assembling being madenegligently without necessary parts.

What is claimed is:
 1. A cleaning apparatus for cleaning an imagecarrier, comprising: a cleaning member for removing a remainingdeveloper left on said image carrier; and a sealing member forpreventing the developer from leaking out at end portions of saidcleaning member, said sealing member having a fabric member contactingan area of said image carrier, which a distance ensuring member, formaintaining a prescribed distance between a developer carrier forcarrying the developer and said image carrier, contacts in thelongitudinal direction of said image carrier, wherein the leaningdirection of fabric on said fabric member is a direction from an endportion to a center portion of said cleaning member when viewed fromupstream of said fabric member in a moving direction of said imagecarrier.
 2. A cleaning apparatus according to claim 1, wherein theleaning direction of the fabric is set in a range of ±45 to ±60 degreesfrom direction from an end portion to a center portion of said cleaningmember, from a viewpoint of a plane substantially parallel to a facewhere said fabric member is supported by a frame of said cleaningapparatus.
 3. A process cartridge detachably mountable to a mainassembly of an image forming apparatus, comprising: an image carrier; adeveloper carrier to carry developer for developing an electrostaticimage formed on said image carrier with the developer; a distanceensuring member to contact said image carrier for maintaining aprescribed distance between said developer carrier and said imagecarrier, a cleaning apparatus for removing a remaining developer left onsaid image carrier; and a sealing member for preventing the developerfrom leaking out at end portions of said cleaning member, said sealingmember having a fabric member contacting an area of said image carrier,which said distance ensuring member contacts in the longitudinaldirection of said image carrier, wherein the leaning direction of fabricon said fabric member is a direction from an end portion to a centerportion of said cleaning member when viewed from upstream of said fabricmember in a moving direction of said image carrier.
 4. A processcartridge capable of being incorporated in an image forming apparatusaccording to claim 3, wherein the leaning direction of the fabric is setin a range of ±45 to ±60 degrees from the direction from an end portionto a center portion of said cleaning member, from the viewpoint of aplane substantially parallel to a face where said fabric member issupported by a frame of said cleaning apparatus.
 5. An image formingapparatus, comprising: an image carrier; a developer carrier to carrydeveloper for developing an electrostatic image formed on said imagecarrier with the developer; a distance ensuring member to contact saidimage carrier for maintaining a prescribed distance between saiddeveloper carrier and said image carrier, a cleaning member for removinga remaining developer left on said image carrier; and a sealing memberfor preventing the developer from leaking out at end portions of saidcleaning member, said sealing member having a fabric member contactingan area of said image carrier, which said distance ensuring membercontacts in the longitudinal direction of said image carrier, whereinthe leaning direction of fabric on said fabric member is a directionfrom an end portion to a center portion of said cleaning member whenviewed from upstream of said fabric member in a moving direction of saidimage carrier.
 6. An image forming apparatus according to claim 5,wherein the leaning direction of the fabric is set in a range of ±45 to±60 degrees from the direction from an end portion to a center portionof said cleaning member, from the viewpoint of a plane substantiallyparallel to a face where said fabric member is supported by a frame ofsaid cleaning apparatus.